In blast hole drilling and the like, it is often desirable to drill at an angle other than vertical. In order to accomplish angle drilling with a typical mobile drilling rig, it is necessary to incline the mast or derrick tower at an angle other than vertical. The incline position of the mast creates a relatively unstable and stressful situation with regard to normal mast deployment apparatus.
In addition, since the normal mast deployment apparatus contains a fixed pivot relative to the base structure or platform, as the tower is inclined at a greater angle, the point of entry of the drill string moves further from the point of support and often outside the area provided for dust collection and the like.
With this invention a transferable and adjustable pivot point for drill mast deployment and a stabilizing support point higher in the mast than previously possible are provided.